University of Alaska Fairbanks researchers and the Alaska Ocean Observing System have released the first digital atlas of historical sea ice concentrations in the Beaufort, Chukchi and Bering seas.

This web-based tool allows users to view and download sea ice concentration data from 1850 to the present.

The university’s Alaska Center for Climate Assessment and Policy and the Scenarios Network for Alaska and Arctic Planning created the sea ice atlas.

With funding support from AOOS, John Walsh, chief scientist at the UAF International Arctic Research Center, and Sarah Trainor, IARC’s ACCAP director, led the project during the past two years. They worked in partnership with the National Snow and Ice Data Center and the University of Illinois, Urbana-Champaign. IARC’s SNAP maintains the data behind the sea ice atlas, which is complementary with other data available at AOOS.

The atlas uniquely provides digitized historical sea ice data compiled from more than 10 sources, including the satellite record, various U.S. Naval and National Ice Center compilations, Canadian records, Danish and Norwegian ship records, and whaling ship reports.

The interactive map allows users to select a date or a location to visualize how open water seasons have varied in a particular place. An animation shows changes in ice extent and concentration through time — year by year and decade by decade. The atlas also offers a glossary that defines different types of sea ice and provides information about the original data sources and how the data were compiled.

One objective is to offer researchers a reliable tool to find time scales of variability.

“Is there a 20-year cycle in sea ice?” Walsh asked. “That is a research question. Researchers want to know about it scientifically. If you only have 30 years of data, it’s really hard to say there is a 20-year cycle. But when you get to 160 years, you can start to see if any cycles hold up over time, whether they are reliable, robust enough to be considered real.”

Researchers are not the only ones who will benefit from the atlas. It provides coastal communities, industry, and state and federal agencies, among others, an objective, historical record of sea ice conditions during the past 160 years. The atlas is also a potential educational tool in the classroom. Anyone with a modern web browser and Internet access is able to use it.

The sea ice atlas will be presented in a webinar hosted by ACCAP Feb. 18 at 10 a.m. Alaska Time. For webinar information, go to http://accap.uaf.edu/node/1048 or contact Tina Buxbaum, 907-474-7812.